Effect of temperature on ultrasonic velocity in steel
- Marathon Oil Co., Littleton, CO (United States). Petroleum Technology Center
The increased mechanical integrity requirements imposed by process safety management regulations (OSHA 29 CFR 1910.119) are forcing more operators to conduct on-stream corrosion monitoring inspections. These inspections rely predominantly on the results of ultrasonic thickness (UT) measurements, which in turn are managed by using commercial software databases. UT equipment vendors such as Krautkramer Branson recommend correcting measured thickness values {minus}0.5% per 100 F, whereas ASTM E797 recommends a {minus}1% per 100 F correction for carbon steel materials. However, little technical literature exists on the topic of UT correction factors as a function of temperature. The consequence of over-correcting a UT measurement may cause premature retirement of a piece of equipment, resulting in an unnecessary outage or material outlay. Therefore, having the appropriate UT temperature correction factors available will increase the reliability of thickness data and ultimately save operators time and money. To identify the effect of temperature on straight beam (0{degree}) ultrasonic thickness values (i.e., changes in the sound velocity), experiments were conducted using carbon steel, two low-alloy steels, and 316 stainless steel materials at temperatures ranging from 70 F to 650 F. Statistical analysis of the data revealed an inverse relationship between temperature and ultrasonic velocity over the test range with a better than 97% confidence level. The change in ultrasonic velocity with temperature also varied depending on the composition of the material. Low alloy steels (i.e., AISI 4130, 4340) were less dependent on temperature than plain carbon steels, while the 316 stainless steel had a greater temperature dependence. A series of graphs, linear regression results, and correction factors are presented for plain carbon steel (C-Mn), AISI 4130 (1Cr-1/4Mo), AISI 4340 (2Ni-1Cr-1/4Mo) and 316 stainless steel (18Cr-12Ni-3Mo).
- OSTI ID:
- 548537
- Report Number(s):
- CONF-970332-; TRN: IM9750%%93
- Resource Relation:
- Conference: Corrosion 97. 52. annual corrosion conference of the National Association of Corrosion Engineers: economics and performance - bridging the gap and NACExpo, New Orleans, LA (United States), 9-14 Mar 1997; Other Information: PBD: 1997; Related Information: Is Part Of Corrosion/97 conference papers; PB: [4584] p.
- Country of Publication:
- United States
- Language:
- English
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